For a politician who has described his faith as a bit like the reception of Magic FM in the Chilterns – it comes in and out – David Cameron is showing a distinct religious streak. The Telegraph leads with "Cameron puts God back into politics", and his intervention gets coverage in most of the papers (though inside, and less than I might have imagined). He has recently spoken about the importance of his Christianity and prayer, the peace he has found from the Eucharist, and now discusses his vision for a more active Christianity in Britain in an Easter article for the Church Times. We had imagined Mr Cameron as low-key CoE, but the fervour with which he has discussed "our Saviour" and – today – urged fellow Christians to be "more evangelical" about their faith reveals him as something altogether more muscular. Arguably, his faith is a private thing and so we cannot know what is in his heart. I suspect he is not quite ready to fall to his knees and pray with an American president, for example. But his approach is a striking departure from the "we don't do God" policy imposed on Tony Blair (without a lot of success, it must be said) by Alastair Campbell.

There was a time of course when faith and Christianity were part of the everyday political discourse. Latterly, and to the often-expressed dismay of senior clerics from all faiths, the subject has been shunted out of the public square. Expressions of faith, or the depiction of Britain as a country not just of faith, but a specifically Christian one, have been frowned upon. The reasons are complex – a combination of militant political secularism, notably in the Labour party, and an anxiety about the growing numerical importance and militancy of other faiths. Politicians have learned to tread carefully, and those whose work is guided by their faith stand out.

Why is Mr Cameron speaking out? It does not follow, after all, that he should make public his private beliefs. We have learned to be sceptical of our politicians and that applies in this case. Could it be that Mr Cameron is anxious to counter the militancy of Christian leaders who have been attacking Government welfare policy? Cardinal Nichols did it this year for the Catholics; yesterday Anglican bishops criticised the growth in for banks. Could it be too that the Prime Minister is aware that part of Ukip's appeal is based on a retro view of Britain? Burnishing his Church credentials speaks, perhaps, to the fears that immigration – Ukip's big issue – is in some way diluting Britain's Christian identity.

There is danger here for Mr Cameron. As our leader argues, "most voters do not want religion squeezed out of public life – but nor do they want to see it used for political purposes". Mr Cameron must tread the line between speaking out for what he believes – good – and appearing to be playing the sectarian card for political advantage. We have been told to see everything the Conservatives do at the moment as being designed to maximise their vote in a tight election, and in particular to see off the threat from the right. They are particularly anxious to win back older, white voters who – coincidentally – are more likely to be preoccupied by thoughts of religion. If it's a choice though, then better he says what he believes, and loudly. Voters can then decide whether they believe in him.